The invention relates to an anatomically shaped seat shell and associated method of construction. Seat shells that are adjusted to the anatomy of the human buttocks or posterior improve sitting stability and reduce the pressure on certain points which usually occurs under the protuberances of the seat bone of the buttocks or posterior. One example of these is the tractor seat, a seat shell molded from sheet steel and perforated. Individually adjusted seat shells, e.g. according to the Shape System of Otto Bock or according to the Silhouette method of Invacaro, offer almost perfect leveling of sitting pressure over the whole sitting area, which is required in difficult cases such as that found in the domain of wheelchairs. In German publications, DE 4405595 and DE 19617912, a further method of this kind is described. However, individually adjusted seat shells of this kind are not suitable or practical for general use.
The present invention is directed to overcoming one or more of the problems set forth above.
In an aspect of this invention, an anatomically shaped seat shell is disclosed. This seat shell includes a first lateral profile and a second lateral profile with a longitudinal axis located between the first lateral profile and the second lateral profile, a median support located edgeways to the longitudinal axis of the seat shell and having an upper edge portion and a lower edge portion, and a plurality of seat bands located transverse to the median support and connected to the upper edge portion of the median support, the first lateral profile and the second lateral profile.
In another aspect of this invention, a method of creating an anatomically shaped seat shell is disclosed. The method includes utilizing a first lateral profile, a second lateral profile, with a longitudinal axis located between the first lateral profile and the second lateral profile, locating a median support edgeways to the longitudinal axis of the seat shell and having an upper edge portion and a lower edge portion, and attaching a plurality of seat bands transverse to the median support and connected to the upper edge portion of the median support, the first lateral profile and the second lateral profile.
Yet another aspect of the invention is to produce an anatomically shaped seat shell for general use. It is based on the fact that while a suspended belt, customary with folding chairs and wheelchairs, can be adjusted to the shape of the buttocks or posterior to some extent, this adjustment is inadequate because it bends one-dimensionally and produces a non-physiological pressure on the trochanter of the person sitting in the chair. Above all, though, the lowest points of the suspended belt are located in the median plane (which divides the human body into a left and right half). In contrast, the lowest points of an anatomically shaped seat shell are located underneath the two seat bone protuberances and underneath the two thighs. In this Invention, the sitting area is divided up into a plurality of seat bands located transversely to the median plane with a slightly different length thereof allows a three-dimensional sitting area. A median support is provided to that the upper edge of the median support raises the plurality of seat bands in the median plane, so the lowest points of the seat shell defined by the plurality of seat bands are moved outwards out of the median plane to underneath the seat bone protuberances and underneath the thighs. What is particularly remarkable is the fact that these lowest points are automatically set at the right point under the weight of the person sitting in the seat, with both broad and narrow buttocks or posterior. This circumstance enables the upper edge of the median support and the length of the seat bands to be designed so that it can accommodate ninety-five percent (95%) of all possible female posteriors.